1893.] DB. C, J. FORSTTH irAJOR ON illOCEJfE SQriRUELS. 199 



the proportion is reversed. The Creodonta, with, on the whole, 

 a simple type of molars, prevailing in the Puerco fauna, this fact 

 has been considered as conclusive for Cope's theory, that the 

 Mammalian molar is derived from a tritiibercular type. 



Secondly, I cannot acknowledge that many of the Puerco molars 

 said to be trituberculate, are really such ; several species of Mio- 

 clcemis, for example, showing a rather complex type. 



Now, considering the fact tliat we meet amongst the so-called 

 trituberculate types with molars which really are septem-, octo-, and 

 novem-tuberculate, it would have been more correct to speak of a 

 triangular type, this shape of the outline being the only thing the 

 molars in question have generally in common. But they are not 

 all even triangular forms, as those presented by " Oonori/ctes" 

 ditrigonus^, ov Periptichus rliahdodon-, show on either side of the 

 principal inner cusp two secondary cusps, and Riitimeyer has 

 recorded similar types from Egerkingen. 



Moreover, Cope is not consistent with his own theory when he 

 expounds his views as to the mutual relations of Creodonta^. The 

 genus Mioclamus, from which all the other Creodonta are said to 

 be derived, possesses the most complex structure of molar of them 

 all ; whilst Mesony.v, whose upper molars present a simple tri- 

 tubercular type, is placed at the end of a series instead of the 

 beginning, as the theory would require. 



1 farther find inconsistencies in his diagram showing " the facts 

 and hypotheses as to the phylogeny of the Mammalia'". Here 

 the Creodonta and Carnivora, as well as all the other placental 

 Mammalia, with the exception of the Cetacea, are traced back 

 by Cope to the Condylartlira. The latter, together with the Mar- 

 supialia, are derived from the Monotremata. This derivation 

 implies that in the opinion of Prof. Cope the Monotrematous teeth 

 must have been constructed on a trituberculate or a still more 

 simple plan ; and it may be remembered that when the first figures 

 of worn teeth of OrmtJiorJn/ncJiKs v.-eY(i published, they were pro- 

 claimed to support the tritubercular theory. But they are now 

 known to be multituberculate ; so I suppose that this being the 

 case, the argument will probably be considered of no value, the 

 Ornitliorliynchus being an aberrant Prototliere. But still the fact 

 remains, and we must deal with it, that the only prototherian 

 teeth known to this day are multituberculate to the extreme. 



If I am not mistaken, the above news of Cope as to the mutual 

 relations of the different orders of Mammals, — views which are in 

 opposition ^nth trituberculism, — show that their author is on his 

 way, unconsciously perhaps for the present, to become a partisan of 

 the multitubercular origin of Mammalian teeth, so that support 



^ E. D. Cope, 'The Vertebrata of the Tertiary Formations of the West.— I.,' 

 1883, pi. xxiv. d. figs. 2, 4. 



2 76. pi. Ivii. fig. 1«. 



^ ' Synopsis Puerco Fauna,' p. 309. 



^ B. D. Cope, " On the Evolution of the Vertebrates, progressive and retro- 

 gressive," Amer. Naturalist, February, March, April, 1885 (printed April 13, 

 1884), p. 347. 



